1. Field of the Invention
The invention relates to a terminal housing, also known as a header, for electromedical implants such as cardiac stimulators, including implantable cardiac pacemakers and/or cardioverter/defibrillators, neural or brain stimulators, implantable hearing aids or the like.
2. Description of the Related Art
Such electromedical implants usually have a hollow metal housing enclosing a battery and electronic components of the electromedical implant. A terminal housing, also known as a header, having socket contacts which serve as female contacts to receive and provide electric contract for electrode line plugs is permanently connected to the hollow housing of the ready-to-use electromedical implant. Such electrode line plugs are situated on the proximal end of an electrode line, which in its implanted state extends to a location in the body such as one or more chambers of the heart or to a stimulable neural region or cerebral region of a patient at its distal end in its implanted state, where it has stimulation electrodes and/or defibrillation electrodes. The electrodes are electrically connected to corresponding contacts of the electrode line plug. To establish another link to the electronic system in the interior of the hollow housing of the electromedical implant, the terminal housing of the implant has corresponding electric contact elements in the female contacts, which serve to establish electric contact with the corresponding mating contacts of the electrode line plug. The electric contact elements in the female contacts of the terminal housing are in turn electrically connected to the electronic system in the interior of the hollow housing of the electromedical implant. This is usually accomplished via so-called housing feed-throughs, which are provided in the interface between the hollow housing and the terminal housing.
High demands are made of the terminal housing of an electromedical implant, whereby this terminal housing must offer a high reliability in many regards. First, the electric connection between the electric contacts in the terminal housing and the electronic system in the hollow housing of the electromedical implant must be reliable. In addition, the electric contacting between the electric contacts in the terminal housing and the corresponding mating contacts of an electrode line plug must of course also be reliable. Furthermore, high demands are made of the dielectric strength and tightness of the respective female contacts. In addition, the design of the terminal housing must be such that it allows reliable and secure assembly as well as a constantly reliable operation subsequently.
To allow electrode lines of different manufacturers to be connected to electromedical implants of other manufacturers, corresponding industrial standards have been developed which define many properties, in particular the geometry of electrode line plugs and the respective female contacts in the respective terminal housing accordingly. One standard that has been very popular with cardiac stimulators is known by the designation IS-1. A description of this standard can be found in DIN EN 50077. A new standard is known by the designation IS-4. A description of this standard can be found in the draft of the ISO TC 150/SC6NXXX standard.
The existence of at least two different standards leads to even higher demands on the design of a terminal housing for an electromedical implant if this implant should not only support the one standard or the other but instead may possibly also support both standards in parallel.
The high demands of the terminal housing of a cardiac stimulator, for example, have resulted in newer and newer concepts being developed for such a terminal housing. Examples can be found in U.S. Pat. No. 7,083,474, US 2005/0137642, US 2007/0100386 and US 2007/0111587.